This is a commonly asked question. It depends on many factors including your nutritional status, lifestyle, life stage, diet, and often any medications you might be taking. It also depends on the micronutrient – the vitamin or mineral – and how we measure whether it’s working.
This may sound like an attempt to avoid answering what appears to be a simple question, but it isn’t! How supplements work is an interesting and complex subject which we will explore in more detail below.
Understanding what vitamins and minerals do
Vitamins and minerals are micronutrients which play many roles in the body. Often one micronutrient is dependent on another to do its job correctly. Fats, carbohydrates and proteins perform complex jobs in the body, but they are a bit easier to understand.
Simple carbohydrates are a source of energy; proteins support the body with growth and repair. Micronutrients however are involved in a wide range of body activities but at a cellular level.
For example, there are eight B-vitamins, all of which help to create energy but individually they are also involved in a wide range of different body systems. The mineral magnesium is involved in over 300 different interactions in the body!
Type of vitamins
Vitamins A, D, E, and K are fat-soluble. This means they require fat to be absorbed by the body and are stored in our muscles, fatty tissues and liver. All eight B-Vitamins and vitamin C are water-soluble. This means they dissolve in water and are easily absorbed by the body.
Water-soluble vitamins are ready for use by our body much more quickly than fat-soluble vitamins and are used up much more quickly too. This means we need to take them in more regularly through our diet. Because fat-soluble vitamins are stored in the body they are not needed as regularly through the diet (or at the higher doses of water-soluble vitamins.)
How vitamins and minerals work together
Because the effects of many vitamins and minerals are inter-related, the balance between them is important. If we take in more B vitamins to support increased energy levels, they may not do their job as well as they should if our levels of vitamin C, iron and magnesium are not high enough. This might not be because our diet is deficient in these micronutrients: in some cases, this can be due to the use of certain medications that impact on their absorption within the body.
There is an important relationship between vitamin D and calcium. Vitamin D helps the body absorb calcium, so if levels of vitamin D are low, it is difficult to maintain a healthy calcium level without a higher intake of calcium-rich foods or supplements. Plant-based iron (from foods such as spinach, legumes, nuts and seeds) is better absorbed by the body when paired with vitamin C. Vitamin B6 relies on the mineral zinc to function optimally.
Sometimes micronutrients are in competition with each other. For example, zinc and copper compete for absorption in the small intestine. When paired together in a supplement, the ratio of copper and zinc must be carefully balanced otherwise the levels of one can negatively impact the levels of the other.
Why supplement?
Supplementation with micronutrients can help to ensure our body is functioning at its best. Supplements are like an insurance policy – a top up to the daily diet to make sure you are getting everything that you need. Unlike medicines that can often provide quick relief of symptoms, supplements help to keep our body in good health overall, especially as we age. By ensuring we have optimal levels of essential nutrients, we are giving ourselves the best chance to stay healthy for as long as possible.
We are all unique
It is important to remember that we are all individuals and there are many genetic and lifestyle factors which will affect our micronutrient status. If we are suffering with an infection, the body requires more use of certain micronutrients like vitamins C, D and zinc to support our immune function. Digestive health issues can impact our ability to absorb many vitamins and minerals from the food we eat.
Absorption of micronutrients
Vitamins are absorbed by the body in a matter of hours and in some instances can have immediate effects: for example, acting as antioxidants to protect cells, or helping to make hormones. These actions are at a microscopic level and whilst important, we cannot experience them working or feel direct improvements in physical or mental wellbeing as a result. But we know that they are doing their job.
There are several factors that can impact how well micronutrients are working. These factors may prevent your body from absorbing them fully or sometimes not at all.
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Deficiency levels
Extreme deficiency in a particular vitamin or mineral can take a long time to correct. In some cases, a much higher dose of the micronutrient is used to get back to normal levels faster.
For example, if you are diagnosed as deficient in iron (which can cause side effects such as constant fatigue) it can take much longer to build back up to optimal levels using standard lower doses found in some basic multivitamins. 90 per cent of women of childbearing age don’t have adequate blood folate levels, while a third have low iron stores. But ultimately everyone is different.
Even though we need to eat certain essential micronutrients every day through our diet, the body is amazingly robust. It is often weeks, months, and in some cases years before the physical effects of a deficiency can be seen. For example, scurvy – due to a lack of vitamin C - takes two to three months before symptoms to start to show. At the other end of the scale, our body’s store of vitamin B12 may take two to four years to become fully depleted.
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Lifestyle and habits
Certain lifestyle factors and habits, such as high caffeine intake and smoking, can cause malabsorption of essential vitamins and minerals. For example, smoking is known to negatively impact on vitamin D status in some people. High caffeine intake can block the absorption of certain nutrients such as vitamin B6, calcium, iron, and magnesium.
These lifestyle factors mean that we need a higher intake of these micronutrients to maintain a healthy balance.
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Health issues
Certain health issues can also impact on the absorption of essential nutrients. Some of us cannot absorb certain vitamins due to digestive health issues like coeliac disease or inflammatory bowel syndrome. Obesity increases the body’s inflammatory response, which increases the requirement for anti-inflammatory nutrients such as omega-3s.
Always discuss any concerns you may have about a health condition and your nutrient status with a healthcare professional.
What are the signs that supplementation is working?
Signs of deficiencies and how supplementation counteracts these are usually the best ways to tell if it is working. It is unlikely that you will experience anything obvious or dramatic unless you have ongoing issues such as fatigue, poor hair, skin and nails, or perhaps you are always catching the latest cold. If there is a chronic lack of certain micronutrients – and this is corrected through supplementation – over time, you might find you have more energy, better skin, or don’t get ill as often.
But it is important to note that these health issues might not be due to a nutrient deficiency – there may be another underlying reason – so always consult your healthcare professional for advice.
Individual vitamins vs multivitamins
Unless there is a need to combat a specific nutrient deficiency, a multivitamin is a good option. However, often the levels of certain vitamins and minerals that can physically fit into a multivitamin tablet or capsule can be a limiting factor. So, when extra levels of micronutrients are needed, they can be topped up with doses of individual specific supplements.
How long should you wait before changing vitamins?
Three months should be long enough to assess whether you feel any benefits. If you have been diagnosed with a deficit in a specific vitamin then it is important to take the recommended supplements as directed by your healthcare professional. If you are taking supplements for your general health or as a precaution, then you can decide on whether you want to change your supplements or add in additional supplements depending on your wellbeing and how you feel.
So, how long does it take for supplements to work?
When it comes to feeling the benefits, there’s no single answer, thanks to all the factors we have looked at which impact vitamin absorption. It may well be that some benefits can take years to become fully apparent: for example, long-term deficiency of vitamin D might only be discovered if we are diagnosed with osteoporosis in older age and cannot be corrected with a quick fix supplementation programme. But if we never get osteoporosis, one of the reasons may be because we have always had adequate vitamin D levels.
So, as explained at the beginning of this blog, what seems like a simple question is in fact quite a difficult question to answer. And if anyone suggests it isn’t, don’t believe them!
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